1. Field of the Invention
The present general inventive concept relates to an electronic apparatus and a method to drive one or more internal units thereof, and more particularly, to an electronic apparatus capable of preventing a peak current from being introduced into internal units of the electronic apparatus when the internal elements are simultaneously activated and a method to control drive thereof.
2. Description of the Related Art
In general, an electronic apparatus includes various integrated circuits such as a controller to realize various functions, performance of a high speed operation, and miniaturization of the apparatus.
The integrated circuits are driven by simultaneously activating internal elements such as a transistor and an inverter. In an embodiment in which the internal elements are simultaneously activated, a peak current is introduced into the internal elements.
Hereinafter, as an example, an electronic apparatus such as an ink-jet printer will be described to explain a process in which a peak current is introduced into the internal elements.
FIG. 1 is a block diagram schematically illustrating a general ink-jet printer. FIG. 2 is a waveform view to illustrate a method to control the ink-jet printer illustrated in FIG. 1. In FIGS. 1 and 2, only those sections of the ink-jet printer which are associated with an ink emitting process are illustrated and the other sections thereof are omitted.
FIGS. 3 to 5 are views illustrating distortion of a data signal by a peak current.
Referring to FIG. 1, a general ink-jet printer includes a system controller 20, a head controller 30, and a nozzle unit 40.
The system controller 20 transmits a control signal and a data signal to the head controller 30 after receiving printing data input from a host apparatus such as a computer (not illustrated) and performing signal-processing of the printing data.
The head controller 30 and the nozzle unit 40 are generally formed of one head chip.
The head controller 30 receives the control signal and the data signal from the system controller 20, and controls the nozzle unit 40 so that ink can be spat onto a printing paper and an image corresponding to the printing data can be formed. For this, the head controller includes a controller 32 and a signal generator 34.
The controller 32 generates a clock signal L_CLK to control heaters formed in the nozzle unit 40 in a unit, e.g. in a predefined group unit on a basis of a clock signal input from the system controller 20 and provides the clock signal L_CLK to the signal generator 34.
If the clock signal L_CLK is input from the controller 32, the signal generator 34 generates a drive pulse DS having a predetermined pulse width to drive the nozzle unit 40.
The nozzle unit 40 includes an ink supply hole formed from an ink cartridge to a rear surface of a chip to supply ink of cyan, magenta, yellow, and black colors, an ink chamber storing the supplied ink, heaters providing a heat source of a predetermined temperature to emit the ink by expanding the ink on a basis of the drive pulse DS provided from the signal generator 34, and nozzles to emit a desired amount of the ink expanded by the heaters in a desired direction.
Then, the nozzle unit 40 includes several tens of or several hundreds of nozzles, and each of the nozzles includes a heater to emit the ink.
The heater includes a switching device such as a transistor to turn on and off the heater to drive the heater. Therefore, in the case where the heaters are simultaneously activated by providing the drive pulse DS to a head chip, the plurality of heaters are generally simultaneously driven to emit ink through the nozzles and a peak current as indicated by the point A and the point B of FIG. 2 is instantaneously introduced into an interior of the head chip when the switching devices are turned on.
As the peak current is introduced into the interior of the head chip by simultaneously driving the internal elements, an overshoot voltage and an undershoot voltage as illustrated in FIG. 3 are generated.
Further, a ring back voltage formed close to maximum and minimum margins capable of recognizing the logic values 0 and 1 of the data signal as illustrated in FIG. 4 is generated.
As illustrated in FIG. 5, the overshoot voltage, the undershoot voltage, and the ring back voltage generates an error during compensation of a signal.
Further, the introduction of the peak current increases an amount of energy increasing in proportion to a magnitude of a current, thereby increasing an electromagnetic interference (EMI).